Electrical coupling with two sleeve-connected plugs



Sept. 27, 1966 HAMM 3,275,967

ELECTRICAL COUPLING WITH TWO SLEEVECONNECTED PLUGS Filed Sept. 2, 1965 4 Sheets-Sheet 1 Erich Hamm INVENTOR.

Attorney E. HAMM Sept. 27, 1966 ELECTRICAL COUPLING WITH TWO SLEEVE-CONNECTED PLUGS 4 Sheets-Sheet 2 Filed Sept. 2, 1965 Fig.7

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F Erich Hamm INVENTOR.

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i3 9 WA Attorney Sept. 27, 1966 E. HAMM 3,275,967

ELECTRICAL COUPLING WITH TWO SLEEVE-CONNECTED PLUGS Filed Sept. 2, 1965 4 Sheets-Sheet 5 Fig.11

Erich Hamm INVENTOR.

Attorney E- HAMM Sept. 27, 1966 ELECTRICAL COUPLING WITH TWO SLEEVE-CONNECTED PLUGS 4 Shee ts-Sheet 4 Filed Sept. 2, 1965 Erich Hamm INVENTOR BY L y Mk" 5 0411A Attorney United States Patent 3,275,967 ELECTRICAL COUPLING WITH TWO SLEEVE-CONNECTED PLUGS Erich Hamm, Romerstrasse 151, Wesseling, near Cologne, Germany Filed Sept. 2, 1965, Ser. No. 484,563 Claims priority, application Germany, Jan. 4, 1961, H 41,380; Feb. 23, 1961, H 41,824 9 Claims. (Cl. 339-61) This application is a continuation-in-part of my application Ser. No. 164,063, filed January 3, 1962, now abandoned.

The present invention relates to an electrical connector, adapted to form a socket for a pair of complementary plugs to be thus electrically coupled to each other, and to an electrical coupling including two such plugs or male members in combination with an associated socket or female member into which these plugs are removably inserted from opposite ends.

Known connectors of this type, in which several contact springs or other conductive elements are generally cylindrically arrayed in a substantially rigid supporting sleeve, do not always afford a uniform distribution of current flow through all these elements so that some of them are loaded beyond their rated current-carrying capacity. This is true because equal all-around contact pressure is difiicult to maintain, especially after prolonged use. Moreover, those elements which fail to develop a certain minimum contact pressure tend to accumulate an insulating surface layer, due to dust, atmospheric oxidation and other ambientconditions, which further impairs the current-distribution pattern. Similar conditions exist where the individual conductors are replaced by or combined into a single conductive member, shaped as a longitudinally split sleeve, which of necessity bears nonuniformly upon a plug engaged by it.

It is, therefore, an object of my present invention to provide an improved connector of the type described in which the above disadvantages are avoided. More specifically, the invention aims at providing a connector of this character in which the contact pressure, whose magnitude depends upon the relative dimensioning of the sleeve and plug diameters, will be substantially uniform around the connector axis even in the presence of considerable variations in the design tolerance of plugs to be used therewith and will not be materially affected by a wearing of the parts.

These objects are realized, in accordance with the present invention, by the provision of a radially deformable elongated supporting sleeve of resilient, preferably insulating material, such as natural or synthetic rubber, having a through-going longitudinal bore, the sleeve or at least its inner peripheral wall being advantageously cylindrical although prismatic configurations, e.g. with cross-sections in the form of a regular polygon, may be tolerated in some instances. The bore, in any event, is to be of constant cross-section over at least a major portion of its length, thus with the possible exception of certain locations where a shoulder, an annular groove or some similar formation may be provided for the purpose of helping maintain an array of stiff elongated conductor elements and substantially identical conductor elements which are so disposed inside the bore as to be tangent to the periphery of an imaginary circular cylinder coaxial with the bore. These elements, extending almost or completely from one end of the bore to the other in a direction parallel to the axis of the aforementioned imaginary cylinder, are free to yield radially outwardly, i.e. away from that axis, upon being engaged by a pair of mating plugs inserted into the sleeve through opposite ends of the bore. These plugs are also of constant cross- 3,275,967 Patented Sept. 27, 1966 section over all or nearly all of their inserted length and are so dimensioned as to exert an outward contact pressure upon the conductor elements of the sleeve engaged thereby. Thus, the plugs are in pressure-transmitting conductive contact with these elements along respective longitudinal parallel zones having the same distance from the plug axis; if, as will usually be the case, the sleeve and the plugs are cylindrical, the diameter of each plug is slightly greater than that of the imaginary cylinder.

As long as the plugs are not inserted, the conductor elements may be held in position within the sleeve by temporary or permanent retaining means, e.g. a resilient ring wedged into the array of conductors approximately midway along the bore (thus beyond the ends of the inserted plugs) or a removable insert of cardboard or the like. The conductors may also, in the absence of the plugs, contact one another so as to be retained in position by their mutual engagement. It will usually be convenient, however, to leave one of the plugs in constant engagement with the sleeve and to withdraw only the other plug whenever the connection is to be broken; for this purpose, the first-mentioned plug may be lengthened, roughened on its surface or otherwise provided with means for maintaining its engagement with the conductive array while the other plug is pulled out.

In the preferred case in which the sleeve or at least the wall of its bore is circularly cylindrical, this wall may be provided with longitudinal flutes in which the conductive elements are partly received. With a polygonal sleeve profile, on the other hand, these elements can be conveniently lodged in the corners of the polygon.

In all the instances described, there will be at least three conductor elements in the array of the connector sleeve embodying the invention. These elements, or groups thereof, may also be used to establish separate current paths through the coupling if the contact zones of the plugs are mutually insulated so that two or more circuits exist by way of corresponding zones of the two plugs and respective conductor elements aligned therewith. In such case it will be desirable to provide the sleeve with locating means for preventing incorrect insertion of the plugs and maintaining an invariable alignment between the conductor elements and the associated contact zones (of the plugs.

Theinvention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is a longitudinal sectional view of a connector according to the invention;

FIG. 2 is a cross-sectional view taken on the line II-II of FIG. 1;

FIG. 3 is a view similar to FIG. 1, showing the connector thereof together with a pair of plugs matingly received therein;

FIG. 4 is a cross-sectional view taken on the line IV-IV of FIG. 3;

FIGS. 5, 7, 9 and 11 are further views similar to FIGS. 1 and 3, showing additional modifications;

FIGS. 6, 8, l0 and 12 are cross-sectional views taken on the lines VIVI, VIII-VIII, X--X and XIIXII of FIGS. 5, 7, 9 and 11, respectively; and

FIGS. 13 and 14 are two cross-sectional views of further modifications.

In FIGS. 1 and 2, I have illustrated a cylindrical sleeve 2 of insulating resilient material having a bore lined by an array of elongated conductor elements 3 in the form of stiff wires or rods. The conductors 3 are continuously disposed along the inner wall of sleeve 2 and are held against substantial axial displacement by being formed with bent extremities 3a which are imbedded in and thus anchored to the sleeve near the open ends of its bore. Two male coupling members or plugs 1', 1", illustrated in dot-dash lines in FIG. 1, are insertable into the sleeve 3 2 at opposite ends. These plugs are of a diameter slightly exceeding that of an imaginary cylindrical surface C (FIG. 2) which is tangent to all the rods 3 in the absence of the plugs and is centered upon the common axis A of the sleeve and the plugs.

FIGS. 3 and 4 show the plugs 1', 1" inserted into the sleeve 2 so that the conductors 3 thereof are forced radially outwardly against the restraining force of the elastic sleeve. Prior to the introduction of the plugs, a temporary insert such as a cardboard tube (not shown) may have been placed inside the sleeve 2 to help retain the rods 3 in position if necessary; it will be apparent that, if the sleeve 2 is not subject to rough handling, the contiguity of the conductors 3 will sufiice .to prevent their dislodgement. As will be apparent from a comparison of FIGS. 2 and 4, the insertion of plugs 1 and 1" expands the array of conductors 3 whereby contact between them may be broken; the outer diameter of the sleeve, however, is not necessarily increased by such insertion to any appreciable extent.

If it is desired to maintain one of the plugs engaged at all times by the conductor elements 3, the surface of this plug may be roughened as illustrated for the plug 1" in FIG. 3; this results in an increased frictional resistance between the plug and rods 3 which prevents their disengagement even when the two plugs are pulled apart to break the connection. In such event only the smoothsurfaced upper plug 1' will be detached from the sleeve 2 and may subsequently be reinserted without difficulty since the rods 3 maintain their spacing on account of the presence of plug 1b. As further shown in FIG. 3, each of the plugs 1, 1" has a reduced portion surrounded by and secured to an insulating head 4, 4 which facilitates the handling of the coupling without danger of shocks or short circuits.

In FIGS. 5 and 6 I have shown a sleeve 102 whose inner cylindrical wall surface is formed with a multiplicity of longitudinal grooves or flutes 105 individually accommodating the conductor elements 103 in peripherally spaced relationship. A temporary insert 106 of the type described above, designed to hold the conductors 103 in position, has also been illustrated in these figures. The extremities of the sleeve 102 are turned inwardly to form shoulders 102a abutting the ends of the rods 103 to prevent their longitudinal displacement. The connector of FIGS. 5 and 6 functions in essentially the same manner as that of FIGS. 1-4.

In FIGS. 7 and 8, I show another such connector which differs from that of FIGS. 5 and 6 only in that the conductor elements 203 are formed with reduced central portions 203a accommodating a split ring 207 which serves as a permanent retaining means therefor. Ring 207 is disposed midway within the bore of sleeve 202 so as to lie beyond the end of a pair of plugs, not shown, to be introduced into the sleeve as heretofore described.

In FIGS. 9 and 10, I have shown a pair of sleeves 302A, 3023, each similar to sleeve 2 of FIGS. 1-4 but formed at one end with a shoulder 303a, 3031) as an abutment for a respective array of conductor rods 303A, 303B. Each array of rods 303A, 303B is engaged, as before, by a pair of mating plugs 301A, 301A" and 301B, 3018". Each pair of adjacent plugs on the same side of the connector sleeves is threadedly supported on a common insulating base designated 308 for the plugs 301A, 3018 and 308 for the plugs 301A", 3013". As here shown, furthermore, the plugs 301A, 301B are somewhat longer than their counterparts 301A, 3018" so as to be frictionally retained in the sleeves 302A, 30213 when the plugs 301A", 301B" are removed therefrom. Also, the base 308' of the permanently inserted plugs, located opposite the shoulders 303a, 303b, bears directly upon the ends of the rods 303A, 303B.

The sleeves 302A, 302B are shown interconnected by a web 309 to form a unit. Also, the bore of sleeve 302B is shown slightly larger than that of sleeve 302A and the 4 plugs 301B, 301B" have a correspondingly larger diameter than the plugs 301A, 301A" to prevent the reversal of the connections. Thus, the connectors 302A, 302B, 309 serve to establish two distinct electric circuits by way of plugs 301A, 301A" and 301B, 301B", respectively.

FIGS. 11 and 12 represent a one-sleeve coupling according to the invention adapted to set up a plurality of independent circuits. Its sleeve 402 differs from either of the sleeves 302A, 302B of the preceding embodiment merely by the presence of a pair of diametrically opposite longitudinal ribs 40211, 40215 adapted to engage in longitudinal slots formed in the associated plugs 401', 401". Each of these plugs comprises a pair of nearly semicylindrical conductive portions 401A, 4018' or 401A", 4013" interconnected by an insulating web 409' or 409", respectively; the ribs 402a and 4021) enter the clearances defined by the spacing of the two conductive portions to secure each of the plugs against rotation. Furthermore, the slot-s may be unequal width for positively locating the plugs with reference to the sleeve and to each other; thus, as seen in FIG. 12, rib 4021) is slightly wider than rib 402a and the slots defined by the corresponding plug portions are similarly dimensioned. Two semicircular arrays of conductor rods 403A, 403B are respectively engaged by the conductive portions 401A, 401A" and 40133, 401B" of the two plugs. Suitable connections, not further illustrated, extend from the projecting shanks of these portions.

FIG. 13 gives an example of a prismatic sleeve 502 having an equilaterally triangular profile. Conductor rods 503 are disposed at the corners of the triangle and are in contact with respective conductive zones 501A, 5013, 5010 of a plug 501; the conductive plug zones are insulated from one another by a dielectric core 509. As in the preceding embodiment, plug 501 urges the conductors 503 radially outwardly and is in pressure-transmitting contact therewith for the establishment of separate conductive paths to corresponding zones of a confronting second plug.

FIG. 14 illustrates another prismatic sleeve 602 with six conductors 603 disposed at the corners of its hexagonal cross-section. The associated plug 601 has an insulating core 609 separating three conductive zones 601A, 6013, 601C each contacting two of the elements 603. Plug 601 is here shown to be also hexagonally profiled so as to be stable against rotation. Keyways (e.g. as shown in FIG. 11 or 12) or other locating means may, of course, also be provided in the embodiments of FIGS. 13 and 14 to insure that each conductive plug portion always engages the same conductor rod or rods assigned to it; such internal locating means, however, will not be needed where the sleeve forms part of a multiconnector unit and the plugs are interCnnected by common bases in the manner illustrated in FIGS. 9 and 10.

Naturally, any of the various plug and sleeve shapes may be used in combination with such ancillary features as the provision of a roughened surface (FIG. 3), unequal plug lengths (FIG. 9) or multiple connectors (FIGS. 9 and 10); these and other modifications, readily apparent to persons skilled in the art, are intended to be embraced in the spirit and scope of the invention as defined in the appended claims.

I claim:

1. An electrical connector comprising a radially deformable elongated supporting sleeve of resilient material provided with a through-going longitudinal bore, said bore being of constant cross-section over at least the major portion of its length, and an array of at least three substantially identical stiff and mutually unconnected elongated conductor elements tangent to the periphery of an imaginary circular cylinder coaxial with said bore, said elements linging the Wall of said bore and extending substantially throughout the length thereof in a direction parallel to said axis with freedom of independent individual displacement away from said axis, against the sole resistance of said resilient material, under pressure of a pair of mating plugs inserted into said bore from opposite ends, each of said elements having its extremities anchored to opposite ends of said sleeve.

2. An electrical connector comprising a radially deformable elongated supporting sleeve of resilient material provided with a through-going longitudinal cylindrical bore, said bore being of constant cross-section over at least the major portion of its length, and an array of substantially identical stifi and mutually unconnected elongated conductor elements tangent to the periphery of an imaginary circular cylinder coaxial with said bore, said elements lining the wall of said bore and extending substantially throughout the length thereof in a direction parallel to said axis with freedom of independent individual displacement away from said axis, against the sole resistance of said resilient material, under pressure of a pair of mating plugs inserted into said bore from opposite ends, said elements being in contact with one another in the absence of said plugs.

3. An electrical connector comprising a radially deformable elongated supporting sleeve of resilient material provided with a through-going longitudinal cylindrical bore, said bore being of constant cross-section over at least the major portion of its length, and an array of at least three substantially identical still and mutually unconnected elongated conductor elements tangent to the periphery of an imaginary circular cylinder coaxial with said bore, said elements lining the wall of said bore and extending substantially throughout the length thereof in a direction parallel to said axis with freedom of independent individual displacement away from the axis, against the sole resistance of said resilient material, under pressure of a pair of mating plugs inserted into said bore from opposite ends, the wall of said bore is a circular cylinder with longitudinal flutes partly receiving said elements.

4. A connector as defined in claim 3, further comprising retaining means in said sleeve for securing said elements in position in the absence of said plugs.

5. A connector as defined in claim 4 wherein said retaining means includes a resilient ring bearing upon said elements substantially midway along said bore.

6. An electrical coupling comprising, in combination:

a radially deformable elongated supporting sleeve of resilient insulating material provided with a throughgoing longitudinal bore with rectilinear generatrices, said bore being of constant cross-section over at least the major portion of its length, and an array of substantially identical stiff and mutually unconnected elongated conductor elements tangent to the periphery of an imaginary circular cylinder coaxial with said bore, said elements lining the wall of said bore and extending substantially throughout the length thereof in a. direction parallel to said axis with freedom of independent individual displacement away from said axis;

and a pair of coaxial plugs removably inserted into said sleeve through opposite ends of said bore, said plugs being of constant cross-section substantially throughout their inserted length and having longitudinal peripheral zones in pressure-transmitting conductive contact with said elements whereby the latter are forced radially outwardly against 'the restraining force of said sleeve, the distance of said zones from the plug axis exceeding the radius of said imaginary cylinder, said elements contacting one another in the absence of said plugs.

. An electrical coupling comprising, in combination: radially deformable elongated supporting sleeve of resilient insulating material provided with a throughgoing longitudinal cylindrical bore, said bore being of constant cross-section over at least the major portion of its length, and an array of at least three substantially identical stifi and mutually unconnected elongated conductor elements tangent to the periphery of an imaginary circular cylinder coaxial with said bore, said elements lining the wall of said bore and extending substantially throughout the length thereof in a direction parallel to said axis with freedom of independent individual displacement away from said axis;

and a pair of coaxial plugs removably inserted into said sleeve through opposite ends of said bore, said plugs being of constant cross-section substantially throughout their inserted length and having longitudinal peripheral zones in pressure-transmitting conductive contact with said elements whereby the latter are forced radially outwardly against the restraining force of said sleeve, the distance of said zones from the plug axis exceeding the radius of said imaginary cylinder, said longitudinal zones are mutually insulated for establishing a plurality of independent circuits through corresponding zones of said plugs and respective conductor elements aligned therewith.

8. A coupling as defined in claim 7 wherein said sleeve is provided with locking means for maintaining an invariable alignment between said zones and said elements.

9. A coupling as defined in claim 6 wherein one of said plugs is provided with means for maintaining it is engagement with said elements upon withdrawal of the other plug from said sleeve.

References Cited by the Examiner UNITED STATES PATENTS 2,396,725 3/ 1946 Thomas 339205 X 2,681,441 6/1954 Linn 339-262 X 2,956,107 10/ 1960 Monashkin 339-205 X 2,958,843 11/1960 Long 339-61 3,086,190 4/1963 Neidecker et al. 339-205 X FOREIGN PATENTS 556,535 10/ 1943 Great Britain.

EDWARD C. ALLEN, Primary Examiner.

ALFRED S. TRASK, Examiner. 

1. AN ELECTRICAL CONNECTOR COMPRISING A RADIALLY DEFORMABLE ELONGATED SUPPORTING SLEEVE OF RESILIENT MATERIAL PROVIDED WITH A THROUGH-GOING LONGITUDINAL BORE, SAID BORE BEING OF A CONSTANT CROSS-SECTION OVER AT LEAST THE MAJOR PORTION OF ITS LENGTH, AND AN ARRAY OF AT LEAST THE SUBSTANTIALLY IDENTICAL STIFF AND MUTUALLY UNCONNECTED ELONGATED CONDUCTOR ELEMENTS GANGENT TO THE PERIPHERY OF AN IMAGINARY CIRCULAR CYLINDER COAXIAL WITH SAID BORE, SAID ELEMENTS LINGING THE WALL OF SAID BORE AND EXTENDING SUBSTANTIALLY THROUGHOUT THE LENGTH THEREOF IN A DIRECTION PARALLEL TO SAID AXIS WITH FREEDOM OF INDEPENDENT INDIVIDUAL DISPLACEMENT AWAY FROM SAID AXIS, AGAINST THE SOLE RESISTANCE OF SAID RESILIENT MATERIAL, UNDER PRESURE OF A PAIR OF MATING PLUGS INSERTED INTO SAID BORE FROM OPPOSITE ENDS, EACH OF SAID ELEMENTS HAVING ITS EXTREMITIES ANCHORED TO OPPOSITE ENDS OF SAID SLEEVE. 